Glenerie Formation
Laura Mitterman
The Glenerie at a Glance
-A reef environment is suggested by robust fossil forms and a transitional nature.
-Located between the Port Ewen and Esopus formations.
-Thickness ranges anywhere from nine to one hundred thirty feet.
-Covers areas of southeast New York, eastern Pennsylvania, and northwest New Jersey.
-Rock type is bluish gray to medium gray chert and limestone, which becomes pure chert in some places and some pure limestone in other places.
-Rock weathers buff brown in many areas.
(Bordeaux Dissertation, 1999)

 
Here are class members at the Glenerie Outcrop on Rt. 9W in Lower Marion, NY.  In this picture we can see the cherty rock with brownish weathering. The overhang in the forefront of the picture produced some interesting weathering patterns in the rock.

 
This is a picture of an on-site brachiopod with a hammer head for scale.  Brachiopods are one of the most common fossil types found in the Glenerie formation. This particular brachiopod is an articulate brachiopod, possibly of the genera Dolerorthis. 

 
The limestone has weathered in some areas, like the area in the overhang shown above, producing a shell of the fossils exposed.  This piece of the formation shows the weathering, and the fossils are visible sticking out of the rock.  While many brachiopods were found in the outcrop, many sponge spicules and crinoids are also abundant in this formation.

 
Here is a close-up of the weathered limestone at the Rt. 9W outcrop with a hammer pick for scale.  Most of the visible fossils are brachiopods of different genera.  There are many ichnofossils that are plentiful in the Glenerie chert, especially of Zoophycos and Chondrites, although they are not visible in this picture. 
 

 
A nearly complete brachiopod shell is visible in this piece of the formation collected.  The shell is approximately 12mm in width and could possibly be from the genus Cupularostrum. 
This picture shows the underside of a brachiopod valve, with the other valve of the brachiopod missing or destroyed.
Here is a brachiopod that was found preserved with both valves, seen from a different angle than the previous one.
This is a close-up of the outcrop with a rock-hammer for scale. Many different genera of brachiopods are visible in this picture and can be seen from different angles.  There are also a few different types of other fossils that are dispersed among the brachiopods.  This picture was taken at Rt. 9W. 

 
Links

http://www.albany.net/~go/newyorker/albany.html

http://www.hartwick.edu/geology/work/VFT-so-far/VFT.html

http://www.dukelabs.com/On%20the%20Rocks/OTRTable2.htm

http://www.union.edu/PUBLIC/GEODEPT/hollocher/sciencelabs/Labs/helderberg/helderberg.htm

http://www.petrifiedseagardens.org/main.htm
 

 
Laura is a Junior studying paleobiology.  She hopes to attend vetrinary school.

 
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